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This pair aren’t described as being very scary at all. I’ve upped the implied CR (making them a deadly encounter all by themselves for a 1st level party) but the real challenge in taking them on would be the poison garden, or the house of automata.
Medium humanoid, neutral evil
Armor Class 14
Hit Points 85
Speed 30 ft.
STR 12 (+1) DEX 18 (+4) CON 14 (+2) INT 13 (+1) WIS 12 (+1) CHA 14 (+2)
Saving Throws Dex +6, Con +4, Wis +3
Skills Deception +4, Insight +3, Investigation +3, Perception +3, Persuasion +4, Sleight of Hand +6, Stealth +6
Senses Passive Perception 13
Alchemical Innovator: See p78
Callous Genius: Ivana has advantage on Deception, Insight, Investigation and Persuasion rolls unless her opponent is acting selflessly.
Gardens of Evil: See p78, additionally, all saves made against Ivana poisons are rolled with disadvantage.
Closing the Borders: Ivana can close or open Borca’s borders once per day.
Immortal: Ivana is ageless.
Poison Blood: As a bonus action she can coat her weapon with her own, toxic blood. The next strike it does, does +1d4 damage.
Multiattack. Ivana makes two shortsword attacks.
Dagger. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 1d4+4) piercing damage.
Cunning Action. On each of her turns, Ivana can use a bonus action to take the Dash, Disengage, or Hide action.
Sneak Attack (1/Turn). Ivana deals an extra 2d6 damage when it hits a target with a weapon attack and has advantage on the attack roll, or when the target is within 5 feet of an ally of Ivana that isn’t incapacitated and the spy doesn’t have disadvantage on the attack roll.
Medium humanoid, chaotic evil
Armor Class 12
Hit Points 42
Speed 30 ft.
STR 10 (+0) DEX 14 (+2) CON 10 (+0) INT 18 (+4) WIS 14 (+2) CHA 16 (+3)
Skills Deception +5, Insight +4, Persuasion +5, Proficient with watchmaker’s tools.
Senses passive Perception 12
Cursed Correspondence: See p80
Manipulative Actor: Ivan has advantage on Deception, Insight and Persuasion via his letters, or by being out of sight and using a well-practiced child-like voice.
Toy Maker: See p80, he can create facsimiles of animals, monsters and humanoid automata with up to CR 1
Wicked Wonderland: See p81
Closing the Borders: IVan can close or open Borca’s borders once per day.
Rapier. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 1d8 piercing damage.
Parry. Ivan adds 2 to his AC against one melee attack that would hit him, using a parrying dagger in his left hand.
Medium construct, unaligned
Armor Class 15 (natural armor)
Hit Points 40
Speed 30 ft.
STR 14 (+2) DEX 14 (+2) CON 11 (+0) INT Uses Ivan’s WIS Uses Ivan’s CHA Uses Ivans
Senses – Uses Ivan’s
Spider Climb: The Perambulator can ascend walls and walk on ceilings – without unseating Ivan – at half speed.
Protective Shell: The Perambulator must be destroyed first, before attacking Ivan.
Piercing Leg. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 2d6+3 piercing damage.